Dance Silver Springs -- Dub?

[Alexbt]

I'm watching Silver Springs on The Dance... I always thought something looked fishy, but now I'm positive that some of it's an overdub, since I've figured it out myself. It's easier to tell as a pianist, but look at what Christine is playing at the beginning compared to what you hear...

Some of the chords she is shown playing are actually not what is heard (playing low chords, but you hear them high), and some of it doesn't even line up at all.

I know The Dance was filmed/recorded so they could overdub, but this just proves one instance where it was done... and I wasn't tricked!